HYDRO28289 - Laserfiche WebLink

Home Browse Search

Mr. JefjDeatherage RE: Feit Pit SSP November 30, 2004 Page 2 of 4 dewatering pump can be seen on Figure 1. Because the dewatering pump is located within 100 feet of the river, the timing of the stream depletions due to the mining operation is assumed to be instantaneous. If the dewatering pump were to be moved to a different location, an amended SWSP will be submitted to your office for approval. There have been no changes in the mining operation of the site since the previous approval. The mining production rate will remain at an annual average of 100,000 tons, which results in 2.9 acre-feet of water remaining in product hauled off site and 3.1 acre-feet of water used in concrete production each year. Annual water used for dust control will remain approximately 0.8 acre- feet and water used for drinking and sanitary purposes will remain at 0.1 acre-feet. 'T'herefore, the total operation consumptive use will remain approximately 7 acre-feet per year. Table No. 3 shows the operational consumptive use calculations for the Feit Pit mining operation. The updated annual consumptive use for the Feit Pit operation is 45.5 acre-feet. A stream depletion model based on Glover techniques was used to analyze the timing of stream depletions due to consumptive uses. The model was developed under the following assumptions: ~ The depletions are lagged from a centroid location approximately 250 feet from the active stream. • Transmissivity and specific yield values for the mining depletions were assumed as 120,000 gpd/ft and 0.2, respectively. • The distance to the parallel impermeable boundary was assumed to be 4,300 feet. Please see the stream depletion analysis in Appendix A. Lagged stream depletions and annual consumptive uses are compared in Table No. 4. A conservative estimate based on steady-state stream depletions was used for determining monthly lagged stream depletions. GREELEY CANAL NO. 3 SHARES The plan previously approved on August 8, 2000 allowed for 30.9 acre-feet of credit for three shares of Greeley Canal No. 3 (Canal No. 3}, based on a consumptive use per share of 10.3 acre- feet as determined in Case No. 96CW658. This credit is based on 6.74 acres being irrigated by each share. Upon further investigation and based on conversations with Ron Richardson, shareholder of the Canal No. 3 shares, 14 acres were historically imgated by 2 and 13/16ths (2.8125) shares and not 3 shares. According to Mr. Richardson, the shares were historically applied on a number of parcels; however, he is unsure of the location at this time. He has confirmed that 14 acres were historically imgated by the 2.8125 Canal No. 3 shares.